Sum rules in the CFL phase of QCD at finite density

We study the asymmetry between the vector current and axial-vector current correlators in the colour–flavour locking (CFL) phase of QCD at finite density. Using Weinbergʹs sum rules, we compute the decay constant fπ of the Goldstone modes and find agreement with previous derivations. Using Dasʹs sum rule, we also estimate the contribution of electromagnetic interactions to the mass of the charged modes. Finally, we comment on low temperature corrections to the effective field theory describing the Goldstone bosons.